1. Technical Field
The present invention relates to a discharge lamp driving device, a light source device, a projector, and a discharge lamp driving method.
2. Related Art
It is known that melting and solidifying of an electrode is repeated by making the temperature of an electrode of a discharge lamp fluctuate, and growth of a projection, which is a starting point of discharge, formed on a tip of the electrode can be controlled.
As a method of controlling the growth of such a projection, a method of driving a discharge lamp alternately supplying the direct current and the alternating current to a discharge lamp has been proposed (For example, JP-A-2011-23154).
The growth of a projection on the tip of the electrode becomes easily controlled as the fluctuation in temperature of the electrode is made to be large. However, in the driving method described above, the growth of a projection on the tip of the electrode is unlikely to be appropriately controlled in some cases due to the reason that the fluctuation in temperature may not be made to be sufficiently large.
Further, in the above-described driving method, when the electrode of the discharge lamp is heated, the temperature is likely to be rapidly increased and only a projection on the tip of the electrode is extremely melted so that the growth of the projection becomes difficult in some cases.
Accordingly, in the driving method described above, the growth of a projection is suppressed and, as a result, a service life of a discharge lamp is shortened in some cases.